An improved method for the spectrophotometric determination of germanium with phenylfluorone

Abstract

Spectrophotometric determination of germanium with phenylfluorone is considered to be one of the excellent methods, but the reaction is slow and troublesome to carry out. Rate of this reaction is accelerated appreciably by the addition of cethyl trimethyl ammonium chloride (CTMAC) and then the coloration is developed immediately at room temperature (2530°C). The sensitivity is about twice as much as that without CTMAC.The solution containing 18μg Ge is transfered to a 50ml volumetric flask, and enough hydrochloric acid is added to make its total content in the solution equivalent to 5ml of concentrated acid. To this solution are added 5ml of 0.25 percent polyvinyl alcohol (Polmerization grade 1400) solution, 5ml of 1 percent CTMAC solution and 10ml of 0.04 percent phenylfluorone ethanol solution and then it is diluted to 50ml with water. The absorbance of the solution is measured at 505mμ against a blank. The molar extinction coefficient is 1.71×105. The calibration curve shows to be linear over 0.020.16ppm Ge.